Unveiling pressing effects in FDMSP metal–composite parts using in-situ µCT testing

This research focuses on enhancing the utilization of the Fused Deposition Modeling and Sintering (FDMS) process for metal parts by incorporating a pressing step to improve densification and mechanical properties. The study employed aluminum powder in a PLA matrix as the feedstock material and began with process window determination through Finite Element Analysis (FEA). This step mitigated issues such as excessive deformation and void/shrinkage formation in the mid-regions of the parts. Subsequently, defect-free parts underwent heat treatment for debinding and sintering, followed by a pressing operation. Density measurements were performed on three sample types: 3D printed parts, FDMS parts, and Fused Deposition Modeling, Sintering, and Pressing (FDMSP) parts. The FDMSP parts exhibited the highest density, highlighting the significant role of the pressing step. Compressive strength testing revealed an approximate 20% increase in strength for FDMSP specimens compared to FDMS specimens. Additionally, in-situ compression tests aided by µCT analysis revealed that the FDMS specimens initially exhibited a porosity of ∼40%, which decreased to ∼26% after applying a compressive force of 10 kN, underscoring the contribution of the pressing step to compaction. Furthermore, the tests showed an increase in aluminum agglomeration, attributed to the deformation of the PLA matrix under compression, facilitating the redistribution of aluminum particles. These findings confirm the pressing operation’s contribution to improving density and compressive strength, providing a pathway to enhance FDMS processes for metal part manufacturing.